At present, a fuel cell system has been suggested and put to practical use, the system including a fuel cell which receives a supplied reactant gas (a fuel gas and an oxidizing gas) to generate a power. Such a fuel cell system is provided with a fuel supply passage for supplying to the fuel cell the fuel gas supplied from a fuel supply source such as a hydrogen tank.
In recent years, a technology has been suggested in which an injector is disposed in a fuel supply passage of the fuel cell system, whereby the operation state of the injector is controlled to regulate the pressure of the fuel gas in the fuel supply passage (e.g., see Patent Document 1). The injector is an electromagnetic driving type on/off valve in which a valve body is directly driven with an electromagnetic driving force for a predetermined drive cycle and detached from a valve seat, whereby a gas state (a gas flow rate or a gas pressure) can be regulated. A control device drives the valve body of the injector to control the injection timing and injection time of the fuel gas, whereby the flow rate or pressure of the fuel gas can be controlled.    Patent Document 1: Japanese Patent Application Laid-Open No. 2007-165163